1. Field of the Invention
The present invention relates to an all-terrain saddle type vehicle provided with a gear transmission capable of selectively establishing a plurality of speed change steps, a transmitting unit capable of transmitting power from a crank shaft rotatably supported by the crank case of an engine, and a generator connected to the crank shaft.
2. Description of Background Art
An all-terrain saddle type vehicle is disclosed in Japanese Patent Laid-Open No. H7-195949, in which a centrifugal automatic clutch is used as a transmitting unit for transmitting the power of a crankshaft to a gear transmission side. A power transmitting unit using a belt converter mechanism using a V belt is utilized. However, in such a centrifugal automatic clutch or such a belt converter mechanism, a torque amplification operation can not be expected and the number of the speed change steps of a gear transmission considerably increases to complicate the constitution of the gear transmission. In particular, in the power transmitting unit using the belt converter mechanism, a belt needs to be changed at regular time intervals and when water or dirt is attached to the belt, the belt slips to reduce the durability of the belt, which complicates a cooling air system for cooling the V belt because the system that is introduces the cooling air needs to be made waterproof.
In order to considerably reduce the number of the speed change steps of a gear transmission and to simplify the constitution of the gear transmission and to realize a maintenance-free gear transmission, a torque converter may be used instead of the above centrifugal automatic clutch or the belt converter mechanism and a power transmitting unit using such a torque converter is disclosed, for example, in Japanese Patent Laid-Open No. S57-69163. However, the power transmitting unit disclosed in Japanese Patent Laid-Open No. S57-69163 has a constitution in which power from a crankshaft is applied, via a gear train, to the pump of a torque converter whose turbine is coaxially connected to the input shaft of a gear transmission. On the other hand, a power transmitting unit for driving a generator by a crankshaft usually has a generator coaxially mounted on the crankshaft and hence if the arrangement of the torque converter disclosed in the above Japanese Patent Laid-Open No. S57-69163 is applied to the power transmitting unit of an all-terrain vehicle provided with the generator as it is, the crankshaft is placed out of balance in load at both its ends.
The present invention has been made in view of above circumstances, and it is an object of the present invention to provide an all-terrain saddle type vehicle capable of simplifying the constitution of a gear transmission using a torque converter and keeping load in balance at both ends of a crankshaft.
In order to accomplish the above object, a first aspect of the invention is an all-terrain saddle type vehicle including a gear transmission capable of selectively establishing a plurality of speed change steps. A transmitting unit is provided that is capable of transmitting power from a crankshaft rotatably supported by the crank case of an engine to the gear transmission. A generator is connected to the crankshaft. The transmitting unit is a torque converter having a pump rotated by the power from the crankshaft. The torque converter, a lock-up clutch mounted on the crank case side of the torque converter and capable of directly connecting the pump to the turbine of the torque converter and a driving gear rotating integrally with the turbine and capable of transmitting the output of the torque converter to the gear transmission are mounted on one end side of the crankshaft outside the crank case wherein the lock-up clutch is sandwiched between the torque converter and the driving gear and that the generator is mounted on the other end side of the crank shaft outside the crank case.
According to the constitution described above, it is possible to considerably reduce the number of speed change steps of the gear transmission, to simplify the constitution of the gear transmission, to improve durability, and to establish a maintenance-free all-terrain saddle type vehicle by using the torque converter having a torque amplifying function as the transmitting unit capable of transmitting power from the crankshaft to the gear transmission. Further, since the torque converter is mounted on one end side of the crankshaft and the generator is mounted on the other end side of the crankshaft, it is possible to keep the load in balance at both the ends of the crankshaft and to increase the power transmitting rigidity from the crankshaft to the gear transmission by compactly arranging the torque converter, the lock-up clutch, and the driving gear outside the crank case at the position near to the crank case.
A second aspect of the present invention includes a starting clutch capable of transmitting power between the pump of the torque converter and the crankshaft or interrupting the transmission of the power is arranged such that the torque converter is sandwiched between the starting clutch and the lock-up clutch. According to such a constitution, it is possible to compactly arrange a starting clutch capable of transmitting the power between the crankshaft and the torque converter or interrupting the transmission of the power according to the running condition of the all-terrain saddle type vehicle, the torque converter, and the lock-up clutch.
A third aspect of the present invention includes a valve system driving cam chain of a 4-cycle overhead cam type engine that is interposed between the driving gear and the crank case. According to such a constitution, it is possible to reduce the size of a power transmitting unit in the direction along the axis of the crank shaft by effectively arranging the valve system driving cam chain having a narrow width along the axial direction of the crankshaft in a space between the driving gear and the crank case.
A fourth aspect of the present invention includes a cover fixed to the crank case to form an operation chamber between itself and the crank case, and that the generator and the gear transmission both of which are arranged at the almost same position along the axial direction of the crankshaft are received in the operation chamber. According to such a constitution, it is possible to mount or dismount the generator and the gear transmission in the state where they are removed from the crank case and hence to easily maintain the generator and the gear transmission.
Further, a fifth aspect of the present invention includes an all-terrain saddle type vehicle that further includes a control unit for controlling the operation of the lock-up clutch such that the lock-up clutch is turned to the ON state immediately after the all-terrain vehicle starts in the state where the lowest speed change step in the forward direction is established in the gear transmission. According to such a constitution, since the torque converter is put into the lock-up state immediately after the all-terrain saddle type vehicle starts to eliminate the speed change range of the torque converter to produce a vehicle speed proportional to the rotational speed of the engine, it is convenient for performing work at a constant speed such as planting seeds, dusting agricultural chemicals, or the like.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.